The STX Guider attaches to the front of a FW7-STX filter wheel, turning it into a self-guiding filter wheel. The STX Guider is directly compatible with the AO-X adaptive optics unit.
Self-guiding has long been acknowledged as the best, most accurate way to guide long exposure astrophotos, particularly with commercial SCTs. The single most common complaint however is finding bright stars when guiding through dark or narrowband filters. The STX Guider incorporates a KAI-0340 CCD with 640 x 480 pixels @ 7.4u, which attaches to the front of the STX filter wheel so that the guider picks off light from the guide stars before passing through the filters. This guiding CCD is the same sensor used in the ST-i autoguider. Moreover, the optical elements that transfer the light from the pick-off mirror to the CCD act as a 0.7X focal reducer. The result is a doubling of the field of view of the guiding CCD with a correspondingly greater selection of guide stars.
There are two smaller adjustment knobs on the STX Guider: one for focus and one for moving the pick-off mirror to avoid vignetting. A third knob on the side of the unit locks the adjustments in place once the best focus is achieved. A short cable is provided to connect the STX Guider to the remote guide head port on the camera. The STX Guider is also fully compatible with the AO-X adaptive optics accessory.
The STX Guider consumes only 1.1″ of back focus, and no additional adapters are required. Weighs only 1 lb. Also works with the FW5-STX.